rivi

<p>"one consecutive"? As a non-native speaker the possibilities of the english language continue to astonish me.<br>

But nevertheless, someone at pnet probably reads Pratchett: <em><cite>'Multiple exclamation marks,' he went on, shaking his head, 'are a sure sign of a diseased mind.' (in "Eric")</cite> </em></p>

<p>As on the topic: I can actually imagine products where I would well prefer to buy stuff that has worked over stuff that has to show yet it will work.<br>

<em><br /> </em></p>

<p>I may say that in the good old film days, the only non-edited images <em>ever</em> were slides when viewed in a projector. All others were edited in the process of printing, by choosing gradation (for BW), color correction (for color) etc.. The only difference was that then the photographer had much less control over it. If you are that strict, even a polarizing filter is in some sense "editing", isn't it?</p>

<p>Keep it! Next time they sell an aircraft carrier on ebay you can use this to pay.</p>

<p>Hi,<br>

with the picture you may mean <a href="http://en.wikipedia.org/wiki/The_Falling_Soldier">R. Capa's "<em>Loyalist Militiaman at the Moment of Death, Cerro Muriano, September 5, 1936</em> "</a> (Spanish civil war, not WWI), but in the quotes attributed to him I do not find anything about fortune etc. mentioned (though my search was casual at best).</p>

<p><em>Hmh, Hmh: Astronomy</em> , not astrology.<br>

Red stars are called "late type" by astronomers, they have temperatures of the order of say 3000 to 4500K and therefore glow reddish compared to the sun (which has about 5600K). The blue ones astronomers call "early type" and they can have 10000 to 30000K. The two most easy to spot and famous ones in your picture are alpha and beta Orionis: alpha, in the picture being the are lower left edge of Orion is also named <a href="http://en.wikipedia.org/wiki/Betelgeuse">Betelgeuse</a> , is a late one, glowing reddish with about 3500K. Upper right is beta, called <a href="http://en.wikipedia.org/wiki/Rigel">Rigel</a> , glowing blueish at about 11000K. Your eyes see them not coloured because the color perception is not sensitive enough.</p>

<p>Josh,</p>

<blockquote>

<p>why an advanced amateur would not communicate their gender equally to an advanced pro eludes me</p>

</blockquote>

<p>sorry for the misunderstanding. I meant both they communicate their personality, whether or not the gender is a prominent part of the comminication depends on the person. It is just that you are far more likely to know/recognize the name and style of an advamced pro than that of an advanced amateur.</p>

<p>Average amateurs: Yes in a sense, usually by the portfolio ensemble. It reflects the daily life which, whether we like it or not, still typically has a strong gender specific component, and therefore it might give a godd base for a guess.<br>

Advanced amateurs: No, although there is an individual handwriting I see nothing gender specific in there, or rather say it I feel one of the less important influences to style.<br>

Average pros: No, they're trained to leave individuality behind and deliver what the customers like<br>

Advanced pros: Sort of yes, but only in the sense that they're style might be so unique that you not only tell the gender, but who was the person.</p>

<div></div>

<blockquote>

<p>Does the Gear You have Really Matter?</p>

</blockquote>

<p>Well, depends: For the final picture? Not really. For the owner? Some of them for sure.</p>

<p>If I see that right it looks like a corrupted bit in the compressed file, so that the uncompression of the jpeg from this bit on is shifted in colour and "phase" (the image left border is actually the opixels from the original right side).</p>

<p>Interesting indeed, though I may add that the first pictures form the "dark" backside were taken by Lunik 3 in 1959, using a similar technique, not by the Lunar Orbiters. That's why many of the features there are named like "Gagarin","Mare Moscoviense", etc.</p>

<div></div>

<p>The most simple thing you can do is with ImageMagick:<br>

<br /> convert image1 image2 -compose lighten -composite result<br>

This requires input images to be perfectly aligned on pixel scale. It also does not mask out any cosmics/bad pixels. In gimp, the overlay mode "lighten only" in the layers window does the same.</p>

<p>While most, if not all, up-to-date bodies should have the features you need (10+MP, high ISO (say 6400, coolpix has 400 max.), fast shutter, no delay), a critical point in your situation is the lens. You will want one with as large an aperture as possible. The coolpix maximum aperture is f/2.7-7.6, which means as soon as you start to zoom in things get dim. Very dim. DSLR zoom lenses go dim as well, but not that much. In case you're on a budget a prime focus lenses should be your best option, e.g. 50mm f/1.4 lenses are usually not too expensive. That's already 2 stops better, plus 4 stops from the ISO should bring you where you want.<br>

On a typical DSLR not having a full-frame sensor this is a good focal length for portraits, or full body when you're a bit farther away. If your location does not have enough space for that focal length, I would go for a 35mm or 24mm, again f/1.4, but these might be more expensive.</p>

<p>PS: About no delay: In case there still would be with your DSLR, switch off the autofocus, and prefocus manually. Then there'll be really none.</p>

<p>Born German, but I live in South America, Chile, since 2005. They have a 50Hz 220V system here as well.</p>

<p>Regards, Rivi</p>

<p>Hi Steve,</p>

<p>Pickup noise is very "unreliable". Anything can change it, like orientation of camera, even you yourself being in a slightly different position wrt. camera and noise source.</p>

<p>The way it works it not on the image sensor itself. Sensors, both CCD and CMOS have a single bottleneck though which every pixel passes, namely the gain amplifier. This is the point where pickup noise acts: When the pixel is going through the amplifier while the electromagentic wave going through the camera is in one state, say high, it is altered by adding, say 5 ADU. Less than a nanosecond later the next pixel is amplified, but now the electromagnetic wave is in a slightly different stare, altereing the pixel with a different ADU. So the stripes you see is really the time-pattern of the wave, modulating every single pixel on the way as it is going through the amplifier.</p>

<p>As I say, the way the EM wave goes through the camera is very sensitive to external conditions, and usually camera electronics is shielded well enough to keep the effects out. Exceptionally, however, you get it.</p>

<p>The 50Hz of power supply should be no problem, the EM wave must have MHz to GHz to disturb the readout. Although power plant may create that sort of EM waves as secondary effects, a better guess would be a cell phone or radio tower nearby, or an actual cell-phone right next to the camera.</p>

<p>PS: You see it clearly in the lower left dark parts as well, this runs all over the chip with a few ADU amplitude, you just don't see it in the buildings becuase the local dynamics over the same pixel-distance scale is higher than the amplitude of the noise.</p>

<p>AFAIK it cannot be switched off. This is one of the major snags I have with my K20, since it renders the camera almost useless for astrophotography, when you typically want to take your own darks and subtract them later on.</p>

<p>Looks like detector ("sensor" in photgraphy talk) pickup noise. Can happen if a (rather strong) microwave or VHF/UHF radio emitter (details dpend on the setting of the detector readout, like clocking) is close to the readout electronics. Nothing serious, doesn't do any damage, just spoils that particular picture</p>

<p>Here's is a page showing the IMHO best meteor shower pics I've ever seen: <a href="http://www.moonglow.net/ccd/pictures/meteors/index.html ">http://www.moonglow.net/ccd/pictures/meteors/index.html </a><br>

There are short technical descriptions in the captions that might give you a hint.</p>

 

<p>A single 8h bulb exp will run over. E.g. <a href="http://www.astrosurf.com/sguisard/Pagim/Paranal_from_twilight_to_dawn.html">this</a> was done at a place with the most dark sky on earth, yet it is a composite of 64 ten minute exposures (plus I don't know how much editing).<br>

There are more suggestions in <a href="00T8RH">this thread</a></p>

<p>Two things:<br /> The filters are to be used with a camera and a sensor, I completely agree that you should stay clear of direct sight through the viewfinder by all means.<br /> However, and I say this as a professional astronomer with eclipses under the belt, there is no IR or UV in dangerous amounts during totality. The sun is not dimmed, it is completely covered by the moon, thousands of kilometers of solid silicates between you and the glowing ball. The main radiation during this phase is the pinkish hydrogen emission in the solar flares (prominences), and the scattered light of the corona.<br /> BUT accidents do happen when peop le overestimate the remaining time to the end of totality. Know how long totality is at your spot, make sure you know when it is going to end with a safety margin. <br /> For an exhaustive overview what is and what is not safe, see <a href="http://eclipse.gsfc.nasa.gov/SEhelp/safety2.html">http://eclipse.gsfc.nasa.gov/SEhelp/safety2.html</a></p>

<p>Although I'm a pro in another profession (science), this is the sort of key knowledge scientists need as well: The trick is not to remember the stuff as such, but only how, or where, you found it. If you need it more frequently, you'll remember it automatically better, if not you can go again the way you remember to re-learn without too much effort.<br>

In particular now, as huge online repositories are available, this is easier as ever: If you manage to be consistent in your search terms and strategies, you will find the stuff you need again even after years quite quickly.</p>

<blockquote>

<p>The French photomags I see here, on the other hand, still feature a lot of nude photography, talk about stereotypes!</p>

</blockquote>

<p>JDM, hate to disappoint you, but that French print magazine "Fine Art Photo" is actually German.</p>

<p>Hi,<br>

I am not really sure I understand your question:</p>

<p>Light temperature has nothing to do with the <a href="http://en.wikipedia.org/wiki/Temperature">ambient temperature</a> . Physically spoken, the latter is given by the average kinetic motion of the molecules and atoms. Actually, there is a corresponding light for this temperature, but this is the so-called thermal infrared.</p>

<p>The <a href="http://en.wikipedia.org/wiki/Color_temperature">light temperature</a> photographers talk about is the temperature a black-body would need to have to emit that sort of light. This is convenient because the sun radiates in quite good approximation as a black-body, and the temperature of the sun is of the order of 5800K. This is not dependant on the ambient temperature. The light temparture hitting the film/sensor can be shifted with "colour conversion", or "CC" filters.</p>

<p>Regards, Rivi</p>